login
This site is supported by donations to The OEIS Foundation.
Logo

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A118462 Decimal equivalent of binary encoding of partitions into distinct parts. 1
0, 1, 2, 3, 4, 5, 8, 6, 9, 16, 7, 10, 17, 32, 11, 12, 18, 33, 64, 13, 19, 20, 34, 65, 128, 14, 21, 24, 35, 36, 66, 129, 256, 15, 22, 25, 37, 40, 67, 68, 130, 257, 512, 23, 26, 38, 41, 48, 69, 72, 131, 132, 258, 513, 1024, 27, 28, 39, 42, 49, 70, 73, 80, 133, 136, 259, 260, 514 (list; graph; refs; listen; history; internal format)
OFFSET

0,3

COMMENTS

A part of size k in the partition makes the 2^(k-1) bit of the number be 1. The partitions of n are in reverse Mathematica ordering, so that each row is in ascending order. This is a permutation of the nonnegative integers.

The sequence is the concatenation of the sets: e_n={j>=0: A029931(j)=n}, n=0,1,...: e_0={0}, e_1={1}, e_2={2}, e_3={3,4}, e_4={5,8}, e_5={6,9,16}, e_6={7,10,17,32}, e_7={11,12,18.33.64}, ... . [From Vladimir Shevelev (shevelev(AT)bgu.ac.il), Mar 16 2009]

LINKS

Index entries for sequences that are permutations of the natural numbers

V. Shevelev, A recursion for divisor function over divisors belonging to a prescribed finite sequence of positive integers and a solution of the Lahiri problem for divisor function sigma_x(n) [From Vladimir Shevelev (shevelev(AT)bgu.ac.il), Mar 17 2009]

EXAMPLE

Partition 11 is [4,2], which gives binary 1010 (2^(4-1)+2^(2-1)), or 10, so a(11)=10.

CROSSREFS

Cf. A118463, A118457, A000009 (row lengths).

Cf. A089633 (first column), A000079 (last in each column). [From Franklin T. Adams-Watters (FrankTAW(AT)Netscape.net), Mar 16 2009]

Sequence in context: A194061 A085176 A192179 * A122317 A130992 A122318

Adjacent sequences:  A118459 A118460 A118461 * A118463 A118464 A118465

KEYWORD

base,nonn,tabf

AUTHOR

Frank Adams-Watters (FrankTAW(AT)Netscape.net), Apr 28 2006

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified February 14 22:03 EST 2012. Contains 205668 sequences.